There is a need for safe and efficient vectors for delivery of bioactive agents, such as DNA, RNA, protein or drugs because conventional approaches of viral mediated delivery can cause a virus elicted immune response in the patient, or increase the risk of cancer for the patient.
Nonviral vectors have attracted much attention due to their lack of immunogenic problems. Poly(ethyleneimine)s (PEI) have been widely studied as DNA condensing agents and transfecting vectors. However, PEI polymers show significiant levels of cytotoxicity both in vitro and in vivo and are not biodegradable, which may not be safe for long-term treatment.
Some poly(ester alkyleneimine)s are potentially useful as vectors for delivery of bioactive agents, in part because the polymers are biodegradable and cationic in physiological solutions and have low cytotoxicity. However, the poly(ester alkyleneimine)s known in the art either have limited solubility in physiological conditions, or are difficult to prepare. Many other types of cationic polymers have been suggested for use as vectors exhibit low transfection efficiency relative to PEI and the transfection efficiency can vary depending on the types of cells being transfected.
Therefore, there is a need to develop other biodegradable polymers to overcome the above and other problems. Surprisingly, the present invention meets this and other needs.